An unsolved problem in a multi-component system is the dissemination of data that defines changes to system/component states, settings, or configurations to other interrelated systems/components. In a modularized system consisting of independently developed components, it is not feasible for each system that changes information to know the systems that must react to the change. It is also not efficient for each system to frequently check to see if a change has occurred.
A further problem relates to determining the value that a named data item should assume if there is not an explicit definition of that data item. In many systems, this is determined by the system component that uses the data by a method such as by assuming default values, or by searching for an appropriate definitions in a related data store. In some other systems, accessing such an unspecified data item is an error. Either of these processes have numerous associated drawbacks.